Small Bowel Obstruction (SBO)¶

Alex Wiles

Background¶

Risk Factors: prior abdominal surgeries (adhesions), malignancy, hernia, intestinal inflammation (IBD)/stricture, radiation, abscess, foreign bodies
Indicators for bowel ischemia: fever, leukocytosis, tachycardia, peritonitis
Ddx: early appendicitis, large bowel obstruction, Ogilvie’s, DKA, Pancreatitis, IBD, Gastric outlet obstruction

Nausea, emesis, intermittent colic, bloating, constipation
Obstipation if completely obstructed, loss of flatulence
Exam: classically with “tinkling” bowel sounds, tympanic abdomen, distended abdomen

CBC, BMP, lipase, hepatic function panel, lactate (sensitive, not specific for ischemia)
Start with KUB to rule out perforation but typically will require CT (x-ray only ~80% sensitive)
CT abdomen/pelvis with IV contrast is optimal study if adequate renal function
- No oral contrast (American College of Radiology (ACR) Appropriateness Criteria) as it will not aid diagnosis and can lead to aspiration; IV helps evaluate ischemia
Key word: transition point
Non-specific signs of bowel inflammation: bowel wall thickening, submucosal edema

Consult EGS: if any concern for SBO, evaluate need for urgent surgery
Surgical indications complete obstruction, CT with ischemia, perforation
Gastric decompression: place NGT (prevent aspiration)
NPO until obstruction relieved and NGT removed
Fluids: two large bore IVs (nursing communication); LR bolus + maintenance while NPO
If no resolution of partial obstruction at 48 hours:
Fluoroscopy Upper GI small bowel ft (follow through)
- In comments, write “Gastrografin contrast” (water-soluble contrast) which osmotically reduces bowel wall edema and aids peristalsis
- If gastrografin reaches the colon within 24 hours, it predicts clinical resolution of SBO without surgery
- Note: this can also be therapeutic for pSBO and get bowels moving